Meeting the increased water requirement in agriculture due to the increases of irrigated areas in order to provide food for growing populations, relies on the application of water with increased efficiency. This work evaluated the partial root drying technique for lemon 'Tahiti' trees under semi-arid climate conditions in the north of Minas Gerais. The experiment was carried out in randomized block design with nine treatments and four replicates. Treatments were based on percentages of reduction of calculated irrigation water depth, i.e., 25% corresponding to the reduction of irrigation on one quarter of the area occupied by the plant and 50% corresponding to the reduction of irrigation on half of the plant area during three phonological phases (I, II and III) of lemon 'Tahiti'. The results showed that irrigation scheduling using the partial root drying method may be performed with any of the treatments evaluated. The larger yields and water use efficiencies were obtained for treatments T7 and T8 which were a reduction of 25% of total irrigation every 7 or 15 days during flowering followed by a reduction of 50% of total irrigation every 7 or 15 days in phases II and III.
